This application relates to radiation-sensitive compositions and more particularly to such compositions comprising acrylated esters.
As used in this specification, the term "acrylated esters" refers to either acrylic or methacrylic acid resins. U.S. Pat. No. 4,171,974 describes photosensitive resins that are styrene solutions of methacrylate esters of epoxy resins available as Epocryl (TM) 321 and 322 resins from the Shell Chemical Corporation. Also disclosed are diacrylate esters of liquid Bisphenol A epoxy resins available as Epocryl DRH-302 and 303. Other suitable acrylate esters are prepared from polyepoxy compounds derived from phenol-formaldehyde novolacs of unsaturated functionality up to 3.3.
In U.S. Pat. No. 4,174,307 there are described radiation sensitive compositions which are based on diacrylated oligourethanes. An ultraviolet curable resin now available in a nonvolatile acrylated urethane based on aliphatic isocyanate and sold as CMD 8800 UV/EB Curable Resin by the Celanese Corporation.
Such acrylated resins are especially used in rapid curing ultraviolet light curable coatings. There are a variety of potential uses for these coatings including wood topcoats, coatings for rigid and flexible plastics, floor tile coatings, screen ink coatings and clear coatings, coatings for magnetic tape or disc. An important potential use is as a light-sensitive coating on lithographic plates.
A major drawback in using these radiation-sensitive acrylated esters has been the inhibition to ultraviolet curing in the presence of oxygen, e.g., when carried out in the presence of air. It will be understood therefore that certain commercial limitations arise because of the deleterious effect oxygen has on ultraviolet light curing.